US5093002A - Membrane process for treating a mixture containing dewaxed oil and dewaxing solvent - Google Patents

Membrane process for treating a mixture containing dewaxed oil and dewaxing solvent Download PDF

Info

Publication number
US5093002A
US5093002A US07/726,435 US72643591A US5093002A US 5093002 A US5093002 A US 5093002A US 72643591 A US72643591 A US 72643591A US 5093002 A US5093002 A US 5093002A
Authority
US
United States
Prior art keywords
membrane
cross
polysiloxane
linking agent
silane
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
US07/726,435
Inventor
Mordechai Pasternak
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Texaco Inc
Original Assignee
Texaco Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US07/692,890 external-priority patent/US5102551A/en
Application filed by Texaco Inc filed Critical Texaco Inc
Priority to US07/726,435 priority Critical patent/US5093002A/en
Application granted granted Critical
Publication of US5093002A publication Critical patent/US5093002A/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06—Organic material
    • B01D71/70—Polymers having silicon in the main chain, with or without sulfur, nitrogen, oxygen or carbon only
    • B01D71/701—Polydimethylsiloxane
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
    • C08G77/48—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule in which at least two but not all the silicon atoms are connected by linkages other than oxygen atoms
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G31/00—Refining of hydrocarbon oils, in the absence of hydrogen, by methods not otherwise provided for
    • C10G31/11—Refining of hydrocarbon oils, in the absence of hydrogen, by methods not otherwise provided for by dialysis

Definitions

  • This invention relates to a process for treating a charge containing dewaxing solvent and dewaxed oil. More particularly it relates to use of membrane technology to separate dewaxing solvent from dewaxed oil.
  • hydrocarbon stocks used for the preparation of lubricating oil contain undesirable components which are removed during processing to permit attainment of a product which is characterized by desired properties.
  • a charge stock is subjected inter alia to a dewaxing operation which decreased the wax content and desirably lowers the pour point and the cloud point of the lubricating oil stock.
  • Dewaxing may be effected by mixing a dewaxing solvent, such as methyl ethyl ketone or methyl isobutyl ketone, optionally in the presence of a hydrocarbon such as toluene or xylene, with the charge oil and cooling the mixture below the desired pour point, typically to minus 5° F.-minus 20° F., say minus 10° F., at which point wax precipitates. The wax is filtered; and the dewaxed oil--dewaxing solvent mixture if recovered.
  • a dewaxing solvent such as methyl ethyl ketone or methyl isobutyl ketone
  • a hydrocarbon such as toluene or xylene
  • This recovered mixture has classically been flashed to recover solvent-free lubricating oil stock and solvent which is free of lubricating oil.
  • European Patent Specification 0 125 907 A1 to Wight discloses use of a polyimide membrane containing --CO--NO--linkages.
  • this invention is directed to a process for treating a charge containing dewaxing solvent and dewaxed oil which comprises
  • the lube oil stocks which may be treated by dewaxing may include distillate stocks, deasphalted oils, raffinates fro msolvent extraction of distillate, hydrotreated oils, hydrocracked distillates, etc. typically ranging in viscosity at 100° F. from about 30 SUS to 4,000 SUS. Typically such a charge may be characterized by the following:
  • This waxy oil charge (100 volumes) is mixed with 100-1,000 volumes, preferably 200-500 volumes, say 200 volumes (depending on the viscosity grade and wax content of the feedstock) of ketone dewaxing solvent--such as acetone or preferably methyl ethyl ketone or methyl isobutyl ketone preferably diluted with a hydrocarbon solvent to produce dewaxing solvent.
  • ketone dewaxing solvent-- such as acetone or preferably methyl ethyl ketone or methyl isobutyl ketone preferably diluted with a hydrocarbon solvent to produce dewaxing solvent.
  • dewaxing solvent containing 100-150 volumes of ketone such as methyl ethyl ketone plus 100-50 volumes of a hydrocarbon solvent such as toluene or xylene.
  • the mixture is cooled to minus 5° F.-minus 20° F., say minus 10° F., during which cooling, solid wax precipitates from the waxy oil charge.
  • a mid-continent distillate may be cooled to minus 10° F. to obtain a 0° F. pour point 100 neutral oil.
  • Wax is filtered in a rotary vacuum filter to yield a dewaxed oil filtrate.
  • this filtrate containing dewaxing solvent and dewaxed oil, is passed into contact with, as a separation membrane, a non-porous separating elastomer membrane layer.
  • a composite structure which in one preferred embodiment may include (i) a carrier layer which provides mechanical strength, (ii) a porous support layer, and (iii) a separating elastomer membrane layer across which separation occurs.
  • the composite structure of this invention includes a multi-layer assembly which in the preferred embodiment preferably includes a porous carrier layer which provides mechanical strength and support to the assembly.
  • the Carrier Layer is the Carrier Layer
  • This carrier layer when used, is characterized by its high degree of porosity and mechanical strength. It may be fibrous or non-fibrous, woven or non-woven. In the preferred embodiment, the carrier layer may be a porous, flexible, woven fibrous polyester. A typical polyester carrier layer may be formulated of non-woven, thermally-bonded strands.
  • the porous support layer (typically an ultrafiltration membrane) which may be used in practice of this invention is preferably formed of polyacrylonitrile polymer.
  • the polyacrylonitrile may be of thickness of 40-80 microns, say 50 microns and is preferably characterized by a pore size of less than about 500A and typically about 200A. This corresponds to a molecular weight cut-off of less than about 50,000, typically about 40,000.
  • the separating layer which permits attainment of separation in accordance with the process of this invention includes a non-porous elastomer film or membrane of thickness 1-5 microns, say about 1.5 microns of a polysiloxane polymer of molecular weight M n of about 550-150,000, preferably 550-4,200, more preferably say about 1,750 (prior to cross-linking), which is cross-linked with, as cross-linking agent, (i) a polyisocyanate, or (ii) a poly(carbonyl chloride) or (iii) R 4-a Si(A) a wherein A is --OH, --HH 2 , --OR, or --OOCR, a is 2, 3, or 4, and R is hydrogen, alkyl, aryl, cycloalkyl, alkaryl, or aralkyl.
  • the polysiloxanes which may be employed, as elastomer membranes, in practice of the process of this invention may include membranes of molecular weight M n of 550-150,000, say 1,750 of halogen-free polysiloxanes which contain the repeating unit --Si--O-- and wherein the silicon atoms bear hydrogen or a hydrocarbon group.
  • M n molecular weight
  • halogen-free polysiloxanes which contain the repeating unit --Si--O-- and wherein the silicon atoms bear hydrogen or a hydrocarbon group.
  • the repeating units are of the form ##STR1##
  • R may be hydrogen or a hydrocarbon group selected from the group consisting of alkyl, aralkyl, cycloalkyl, aryl, and alkaryl, including such radicals when inertly substituted.
  • R When R is alkyl, it may typically be methyl, ethyl, n-propyl, iso-propyl, n-butyl, i-butyl, secbutyl, amyl, octyl, decyl, octadecyl, etc.
  • R When R is aralkyl, it may typically be benzyl, beta-phenylethyl, etc.
  • R When R is cycloalkyl, it may typically be cyclohexyl, cycloheptyl, cyclooctyl, 2-methylcycloheptyl, 3-butylcyclohexyl, 3-methlcyclohexyl, etc.
  • R When R is aryl, it may typically be phenyl, naphthyl, etc.
  • R When R is alkaryl, it may typically be tolyl, xylyl, etc. R may be inertly substituted i.e. it may bear a non-reactive substituent such as alkyl, aryl, cycloalkyl, ether, etc.
  • R groups may include 2-ethoxyethyl, carboethoxymethyl, 4-methyl cyclohexyl, p-methylphenyl, p-ethylbenzyl, 3-ethyl-5-methylphenyl, etc.
  • the preferred R groups may be lower alkyl, i.e. C 1 -C 10 alkyl, groups including e.g. methyl, ethyl, n-propyl i-propyl, butyls, amyls, hexyls, octyls, decyls, etc.
  • R may preferably be methyl.
  • halogen-free polysiloxanes are the di-silanol-terminated poly(dimethyl siloxanes) of lower molecular weight, typically 550-150,000, preferably 550-4,200, more preferably, say 1,750.
  • These polysiloxane elastomer membranes which yield good Flux and Separation, may be characterized by the formula: ##STR2## wherein n is about 7-2,000, say 24.
  • polysiloxanes may be polydimethyl siloxanes which are silanol terminated.
  • Illustration polysiloxanes which may be employed may be those set forth in the Table which follows:
  • the silicone membranes are cross-linked.
  • the non-cyclic silicones which bear reactive terminal groups typified by --OH or --NH 2 , they may be cross-linked by (i) a polyisocyanate, (ii) a poly(carbonyl chloride) or (iii) a silane
  • A is --OH, --NH 2 , --OR, or --OOCR
  • a is 2, 3, or 4, and R may be as noted supra.
  • the R groups need not be all the same.
  • cross-linking is effected by reaction between the reactive terminal group of the non-cyclic silicone and the A group of the silane; and accordingly these groups which are to react should be different from each other.
  • the silicone may be amino terminated, more preferably hydroxy terminated, and in the silane, A is preferably --OR or --OOCR.
  • the silane contains the moiety --OR or --OOCR, and the silicone is --OH terminated for example, the cross-linked polymer includes linkages of the type. ##STR3##
  • the silicone may be --OR or --OOCR terminated, in which instance the silane may preferably contain an --OOH moiety. It appears that no cross-linking may occur when the silicone is terminated by hydrogen.
  • the silicone is a cyclic silicone, typified for example by decamethyl cyclopentasiloxane, it will be apparent that the molecule bears no terminal groups.
  • cross-linking is effected by breaking an Si--O bond in the ring by reaction with the cross-linking agents.
  • Typical alkoxy silanes which may be employed may include:
  • Typical acyloxy silanes which may be employed may include:
  • acyloxy silanes may be employed typified by:
  • Illustrative aminosilanes may include dimethyl diamino silane or dibutyl diaminosilane; illustrative hydroxy silanes may include diethyl dihydroxy silane or methyl trihydroxy silane.
  • Typical polyisocyanates may include, the first listed being preferred:
  • Typical poly(carbonyl chlorides) may include, the first listed being preferred:
  • Formation of the cross-linked elastomer silicone membrane may be carried out in a solution, in inert diluent-solvent (typified by a hydrocarbon such as commercial hexane) of 5-15, say 10 w % of the non-halogenated polysiloxane plus 1-10 w %, say 4 w % of cross-linking agent.
  • inert diluent-solvent typified by a hydrocarbon such as commercial hexane
  • This solution may be solvent cast as a 0.5-4 mil, say 2 mil film onto a support layer (on a carrier layer) typically at say 25° C. Thereafter it is cured at 110° C.-140° C., say 125° C. for 10-20 minutes, say 15 minutes to form a film 1-5, say 1.5 thick.
  • a composite membrane which comprises (i) a carrier layer characterized by mechanical strength, for supporting a porous support layer and a separating layer (ii) a porous support layer such as a polyacrylonitrile membrane of 10-80 microns, and of molecular weight cut-off of 25,000-100,000, and (iii) as a non-porous separating layer a polysiloxane elastomer membrane which has been cross-linked with, as cross-linking agent, a polyisocyanate, or a poly(carbonyl chloride) or R 4-a Si (A) a wherein A is --OH, --NH 2 --OR, or --OOCR, a is 2, 3, or 4, and R is alkyl, aryl, cycloalkyl, alkaryl, or aralkyl.
  • a spiral wound module which includes a non-porous separating layer membrane mounted on a porous support layer and a carrier layer, the assembly being typically folded and bonded or sealed along all the edges but an open edge--to form a bag-like unit which preferably has the separating layer on the outside.
  • a cloth spacer, serving as the permeate or discharge channel is placed within the bag-like unit. The discharge channel projects from the open end of the unit.
  • a feed channel sheet--typically formed of a plastic net is then placed on one face of the bag-like unit, adjacent to the separating layer, and coterminous therewith.
  • the so-formed assembly is wrapped around a preferably cylindrical conduit which bears a plurality of perforations in the wall--preferably in a linear array which is as long as the width of the bag-like unit.
  • the projecting portion of the discharge channel of the bag-like unit is placed over the perforations of the conduit; and the bag-like unit is wrapped around the conduit to form a spiral wound configuration. It will be apparent that, although only one feed channel is present, the single feed channel in the wound assembly will be adjacent to two faces of the membrane layer.
  • the spiral wound configuration may be formed by wrapping the assembly around the conduit a plurality of times to form a readily handleable unit.
  • the unit is fitted within a shell (in manner comparable to a shell-and-tube heat exchanger) provided with an inlet at one end and an outlet at the other.
  • a baffle-like seal between the inner surface of the shell and the outer surface of the spiral-wound unit prevents fluid from bypassing the operative membrane system and insures that fluid enters the system principally at one end.
  • the permeate passes from the feed channel, into contact with the separating layer and thence therethrough, into the permeate channel and thence therethrough to and through the perforations in the conduit through which it is withdrawn as net permeate.
  • charge liquid is permitted to pass through the plastic net which serves as a feed channel and thence into contact with the non-porous separating membranes.
  • the liquid which does not pass through the membranes is withdrawn as retentate.
  • the liquid which permeates the membrane passes into the volume occupied by the permeate spacer and through this permeate channel to the perforations in the cylindrical conduit through which it is withdrawn from the system.
  • the system of this invention may be extruded as a fine tube with a wall thickness of typically 0.001-0.1 mm.
  • the extruded tubes are passed through a bath of silicone which is cross-linked and cured in situ.
  • a bundle or these tubes is secured (with an epoxy adhesive) at each end in a header; and the fibres are cut so that they are flush with the ends of the header.
  • This tube bundle is mounted within a shell in a typical shell-and-tube assembly.
  • the charge liquid is admitted to the tube side and passes through the inside of the tubes and exits as retentate.
  • permeate passes through the non-porous separating layer and permeate is collected in the shell side.
  • non-porous cross-linked elastomer separating layer It is a feature of the non-porous cross-linked elastomer separating layer that it is found to be particularly effective when used in a pressure driven process.
  • a pressure driven process a charge liquid containing a more permeable and a less permeable component is maintained in contact with a non-porous separating layer; and a pressure drop is maintained across that layer. A portion of the charge liquid dissolves into the membrane and diffuses therethrough. The permeate passes through the membrane and exits as a liquid.
  • the charge containing dewaxing solvent and dewaxed oil in liquid phase typically at 20° C.-40° C., say 25° C. may be passed into contact with the non-porous elastomer separating layer of the membrane of this invention.
  • a pressure drop of about 500-1,000 psi, say 800 psi is commonly maintained across the membrane.
  • the feed or charge side of the membrane is at pressure sufficient ot drive permeate across the membrane and commonly about 800 psig; and the permeate or discharge side of the membrane is at about atmospheric pressure.
  • the feed is passed over the surface (ca three inches in diameter in one embodiment) of the membrane at a rate (e.g. of about 1,200 ml/min) which minimizes the possibility of concentration polarization.
  • the permeate which passes through the membrane includes increased content of dewaxing solvent and decreased content of dewaxed oil; and the retentate includes increased content of dewaxed oil and decreased content of dewaxing solvent.
  • the permeate may be found to typically contain about 96 w % of dewaxing solvent.
  • Permeate is recovered in liquid phase.
  • Separation may typically be carried out at a flux of 20-40, say 37.1 kilograms per square meter per hour (kmh).
  • the membranes may have a rejection of more than 80% and commonly 70%-90%, say 89.7%.
  • the elastomer separating membrane is formed on the DUY-L brand (of Daicel Corp.) composite which includes as carrier layer the woven polyester backing described supra.
  • the porous support layer is the commercially available polyacrylonitrile (PAN) having a 40,000 molecular weight cut off.
  • This membrane (three inch diameter circle) is mounted in a standard cell. There is admitted to the cell and to the non-porous elastomer separating layer a charge containing one part by weight of dewaxed SNO-100 oil and 1 part by weight of methyl ethyl ketone and 1 part by weight of toluene
  • Separation is carried out at room temperature of 25° C. and a charge (and retentate) pressure of about 800 psig. Feed is at 25° C./800 psig at flow rate of 1,200 ml/min. Permeate pressure is atmospheric. Selectivity is measured and reported as % Rejection which is calculated at 100 ⁇ (the quantity of dewaxed oil in the feed minus the quantity of dewaxed oil in the permeate) divided by the quantity of dewaxed oil in the feed. Clearly a higher Selectivity is desired, as this means that the retentate desirably contains less dewaxing solvent and the permeate desirably contains more solvent. Flux is measured as kilograms per square meter per hour (kmh).
  • Example II the procedure of Example II is followed except that in Example II, the toluene diisocyanate is present in amount of 2%, in Examples III-IV the cross-linking agent is adipoyl dichloride (2 w % and 4 w % respectively) and in Example V, no cross-linking agent is employed.
  • Example II the procedure of Example I is followed except that the polysiloxane is decamethyl cyclopentasiloxane ##STR4## present as 5 w % solution in commercial hexane which also contains 5 w % of a multifunctional cross-linking agent as noted in the Table which follows:

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Water Supply & Treatment (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Health & Medical Sciences (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Nanotechnology (AREA)
  • General Chemical & Material Sciences (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)

Abstract

Charge containing dewaxed oil and dewaxing solvent (typically methyl ethyl ketone and toluene) is treated to separate dewaxing solvent by use of a separating elastomer membrane barrier of a polysiloxane which has been cross-linked as with toluene diisocyanate, adipoyl dichloride, a dialkoxy silane, or a diacetoxy silane.

Description

This is a division of application Ser. No. 07/692,890, filed Apr. 29, 1991, pending.
FIELD OF THE INVENTION
This invention relates to a process for treating a charge containing dewaxing solvent and dewaxed oil. More particularly it relates to use of membrane technology to separate dewaxing solvent from dewaxed oil.
BACKGROUND OF THE INVENTION
As is well known to those skilled in the art, hydrocarbon stocks used for the preparation of lubricating oil contain undesirable components which are removed during processing to permit attainment of a product which is characterized by desired properties. Typically a charge stock is subjected inter alia to a dewaxing operation which decreased the wax content and desirably lowers the pour point and the cloud point of the lubricating oil stock.
Dewaxing may be effected by mixing a dewaxing solvent, such as methyl ethyl ketone or methyl isobutyl ketone, optionally in the presence of a hydrocarbon such as toluene or xylene, with the charge oil and cooling the mixture below the desired pour point, typically to minus 5° F.-minus 20° F., say minus 10° F., at which point wax precipitates. The wax is filtered; and the dewaxed oil--dewaxing solvent mixture if recovered.
This recovered mixture has classically been flashed to recover solvent-free lubricating oil stock and solvent which is free of lubricating oil.
Those skilled in the art have attempted to improve the economics of this process by utilizing membrane technology to separate dewaxing solvent from dewaxed oil. Illustrative of such prior art attempts may be the following:
U.S. Pat. No. 4,985,138 to Pasternak discloses a cross-linked polyimine membrane.
European Patent Specification 0 220 753 A1 to Bitter et al discloses use of a halogen-substituted silicone membrane.
U.S. Pat. No. 4,678,555 to Wernick discloses use of cellulose acetate membranes.
European Patent Specification 0 125 907 A1 to Wight discloses use of a polyimide membrane containing --CO--NO--linkages.
U.S. Pat. No. 4,617,126 to Funk et al discloses use of a polysulfone membrane.
Additional background may be obtained from the references set forth in these patents.
It is an object of this invention to provide a process for treating a charge containing dewaxing solvent and dewaxed oil. Other objects will be apparent to those skilled in the art.
STATEMENT OF THE INVENTION
In accordance with certain of the aspects, this invention is directed to a process for treating a charge containing dewaxing solvent and dewaxed oil which comprises
passing said charge containing dewaxing solvent and dewaxed oil into contact with, as separating membrane, a non-porous elastomer separating polysiloxane membrane layer which has been cross-linked with, as a cross-linking agent, (i) a polyisocyanate or (ii) a poly(carbonyl chloride) or (iii) a silane R4-a Si(A)a wherein A is --OH, --NH2, --OR, or --OOCR, a is 2, 3, or 4, and R is hydrogen of an alkyl, aralkyl, cycloalkyl, aryl, or alkaryl group;
maintaining a pressure drop across said membrane thereby forming a high pressure retentate containing increased content of dewaxed oil and decreased content of dewaxing solvent and a low pressure permeate containing increased content of dewaxing solvent and decreased content of dewaxed oil;
maintaining the pressure on the low pressure discharge side of said membrane above the vapor pressure of said permeate thereby maintaining said permeate in liquid phase;
maintaining the pressure on the high pressure retentate side of said membrane above the vapor pressure of said charge containing dewaxing solvent and dewaxed oil and sufficient to drive permeate across said membrane thereby maintaining said charge dewaxing solvent and dewaxed oil and said retentate in liquid phase;
recovering said permeate containing increased content of dewaxing solvent and decreased content of dewaxed oil; and
recovering said retentate containing increased content of dewaxed oil and decreased content of dewaxing solvent.
DESCRIPTION OF THE INVENTION
The lube oil stocks which may be treated by dewaxing may include distillate stocks, deasphalted oils, raffinates fro msolvent extraction of distillate, hydrotreated oils, hydrocracked distillates, etc. typically ranging in viscosity at 100° F. from about 30 SUS to 4,000 SUS. Typically such a charge may be characterized by the following:
              TABLE                                                       
______________________________________                                    
Property     Range      Preferred  Typical                                
______________________________________                                    
ibp °F.                                                            
             590-900    600-800    675                                    
50% bp °F.                                                         
              725-1100  800-900    850                                    
90% bp °F.                                                         
              800-1350  850-950    920                                    
Viscosity                                                                 
SUS/100° F.                                                        
              35-3500    40-100    54.63                                  
60° F.                                                             
                50-10,000                                                 
                        100-400    348.7                                  
API Gravity  20-30      22-29      25.8                                   
Sp. Gr 15° C./15° C.                                        
             0.870-0.895                                                  
                        0.880-0.890                                       
                                   0.890                                  
Pour Point °F.                                                     
              90-125     95-110    95+                                    
Flash Point °F.                                                    
             360-600    385-560    460                                    
Refractive Index                                                          
             1.4720-1.4940                                                
                        1.4755-1.4920                                     
                                   1.4840                                 
@ 70° C.                                                           
______________________________________
This waxy oil charge (100 volumes) is mixed with 100-1,000 volumes, preferably 200-500 volumes, say 200 volumes (depending on the viscosity grade and wax content of the feedstock) of ketone dewaxing solvent--such as acetone or preferably methyl ethyl ketone or methyl isobutyl ketone preferably diluted with a hydrocarbon solvent to produce dewaxing solvent. In a preferred embodiment, there may be added to 100 volumes of waxy oil charge, dewaxing solvent containing 100-150 volumes of ketone such as methyl ethyl ketone plus 100-50 volumes of a hydrocarbon solvent such as toluene or xylene. The mixture is cooled to minus 5° F.-minus 20° F., say minus 10° F., during which cooling, solid wax precipitates from the waxy oil charge. Typically a mid-continent distillate may be cooled to minus 10° F. to obtain a 0° F. pour point 100 neutral oil. Wax is filtered in a rotary vacuum filter to yield a dewaxed oil filtrate.
In accordance with practice of the process of this invention, this filtrate, containing dewaxing solvent and dewaxed oil, is passed into contact with, as a separation membrane, a non-porous separating elastomer membrane layer.
The Membrane Assembly
Practice of the process of this invention may be carried out by use of a composite structure which in one preferred embodiment may include (i) a carrier layer which provides mechanical strength, (ii) a porous support layer, and (iii) a separating elastomer membrane layer across which separation occurs.
The composite structure of this invention includes a multi-layer assembly which in the preferred embodiment preferably includes a porous carrier layer which provides mechanical strength and support to the assembly.
The Carrier Layer
This carrier layer, when used, is characterized by its high degree of porosity and mechanical strength. It may be fibrous or non-fibrous, woven or non-woven. In the preferred embodiment, the carrier layer may be a porous, flexible, woven fibrous polyester. A typical polyester carrier layer may be formulated of non-woven, thermally-bonded strands.
The Porous Support Layer
The porous support layer (typically an ultrafiltration membrane) which may be used in practice of this invention is preferably formed of polyacrylonitrile polymer. Typically the polyacrylonitrile may be of thickness of 40-80 microns, say 50 microns and is preferably characterized by a pore size of less than about 500A and typically about 200A. This corresponds to a molecular weight cut-off of less than about 50,000, typically about 40,000.
The Separating Layer
The separating layer which permits attainment of separation in accordance with the process of this invention includes a non-porous elastomer film or membrane of thickness 1-5 microns, say about 1.5 microns of a polysiloxane polymer of molecular weight Mn of about 550-150,000, preferably 550-4,200, more preferably say about 1,750 (prior to cross-linking), which is cross-linked with, as cross-linking agent, (i) a polyisocyanate, or (ii) a poly(carbonyl chloride) or (iii) R4-a Si(A)a wherein A is --OH, --HH2, --OR, or --OOCR, a is 2, 3, or 4, and R is hydrogen, alkyl, aryl, cycloalkyl, alkaryl, or aralkyl.
The polysiloxanes which may be employed, as elastomer membranes, in practice of the process of this invention may include membranes of molecular weight Mn of 550-150,000, say 1,750 of halogen-free polysiloxanes which contain the repeating unit --Si--O-- and wherein the silicon atoms bear hydrogen or a hydrocarbon group. Preferably the repeating units are of the form ##STR1##
In the above formula, R may be hydrogen or a hydrocarbon group selected from the group consisting of alkyl, aralkyl, cycloalkyl, aryl, and alkaryl, including such radicals when inertly substituted. When R is alkyl, it may typically be methyl, ethyl, n-propyl, iso-propyl, n-butyl, i-butyl, secbutyl, amyl, octyl, decyl, octadecyl, etc. When R is aralkyl, it may typically be benzyl, beta-phenylethyl, etc. When R is cycloalkyl, it may typically be cyclohexyl, cycloheptyl, cyclooctyl, 2-methylcycloheptyl, 3-butylcyclohexyl, 3-methlcyclohexyl, etc. When R is aryl, it may typically be phenyl, naphthyl, etc. When R is alkaryl, it may typically be tolyl, xylyl, etc. R may be inertly substituted i.e. it may bear a non-reactive substituent such as alkyl, aryl, cycloalkyl, ether, etc. Typically inertly substituted R groups may include 2-ethoxyethyl, carboethoxymethyl, 4-methyl cyclohexyl, p-methylphenyl, p-ethylbenzyl, 3-ethyl-5-methylphenyl, etc. The preferred R groups may be lower alkyl, i.e. C1 -C10 alkyl, groups including e.g. methyl, ethyl, n-propyl i-propyl, butyls, amyls, hexyls, octyls, decyls, etc. R may preferably be methyl.
The preferred of these halogen-free polysiloxanes are the di-silanol-terminated poly(dimethyl siloxanes) of lower molecular weight, typically 550-150,000, preferably 550-4,200, more preferably, say 1,750. These polysiloxane elastomer membranes, which yield good Flux and Separation, may be characterized by the formula: ##STR2## wherein n is about 7-2,000, say 24.
A preferred group of polysiloxanes may be polydimethyl siloxanes which are silanol terminated. Illustration polysiloxanes which may be employed may be those set forth in the Table which follows:
              TABLE                                                       
______________________________________                                    
                         Molecular                                        
                         Weight                                           
______________________________________                                    
A   Silanol terminated                                                    
                    polydimethyl siloxane                                 
                                    550                                   
B   "               "              1750                                   
C   "               "              4200                                   
D   "               "              58,000                                 
E   "               "              110,000                                
F   "               "              150,000                                
G   Acetoxy terminated                                                    
                    "              36,000                                 
H   Methoxy terminated                                                    
                    "              27,000                                 
I   Ethoxy terminated                                                     
                    "               950                                   
J   Carbinol terminated                                                   
                    "              1250                                   
K   Aminopropyl terminated                                                
                    "              2500                                   
    dimethyl                                                              
______________________________________
It is a feature of the process of this invention that the silicone membranes are cross-linked. In the case of the non-cyclic silicones, which bear reactive terminal groups typified by --OH or --NH2, they may be cross-linked by (i) a polyisocyanate, (ii) a poly(carbonyl chloride) or (iii) a silane
R.sub.4-a Si (A).sub.a
wherein A is --OH, --NH2, --OR, or --OOCR, a is 2, 3, or 4, and R may be as noted supra. The R groups need not be all the same.
It will be apparent that cross-linking is effected by reaction between the reactive terminal group of the non-cyclic silicone and the A group of the silane; and accordingly these groups which are to react should be different from each other. Preferably the silicone may be amino terminated, more preferably hydroxy terminated, and in the silane, A is preferably --OR or --OOCR. When the silane contains the moiety --OR or --OOCR, and the silicone is --OH terminated for example, the cross-linked polymer includes linkages of the type. ##STR3##
It will be apparent that the silicone may be --OR or --OOCR terminated, in which instance the silane may preferably contain an --OOH moiety. It appears that no cross-linking may occur when the silicone is terminated by hydrogen.
When the silicone is a cyclic silicone, typified for example by decamethyl cyclopentasiloxane, it will be apparent that the molecule bears no terminal groups. In this instance, cross-linking is effected by breaking an Si--O bond in the ring by reaction with the cross-linking agents.
It will be apparent that when A is --OR, the compound is an alkoxy silane; and when A is --OOCR, the compound is an acyloxy silane. When A is --NH2 OR --OH, the compound is an aminosilane or a hydroxy silane.
Typical alkoxy silanes which may be employed may include:
              TABLE                                                       
______________________________________                                    
methyl          triethoxy    silane                                       
dimethyl        diethoxy     silane                                       
dimethyl        dimethoxy    silane                                       
ethyl           trimethoxy   silane                                       
phenyl          triethoxy    silane                                       
benzyl          trimethoxy   silane                                       
p-tolyl         trimethoxy   silane                                       
1,2-dimethoxy   tetramethyl  disilane                                     
tetramethoxy                 silane                                       
______________________________________
Typical acyloxy silanes which may be employed may include:
              TABLE                                                       
______________________________________                                    
dimethyl       diacetoxy     silane                                       
methyl         triacetoxy    silane                                       
diethyl        diacetoxy     silane                                       
dipheny        diacetoxy     silane                                       
benzyl         tri acetoxy   silane                                       
p-tolyl        tri acetoxy   silane                                       
               tetra acetoxy silane                                       
1,2-di-acetoxy tetramethyl   disilane                                     
1,2-dimethyl   tetra acetoxy disilane                                     
______________________________________
Mixed alkoxy, acyloxy silanes may be employed typified by:
              TABLE                                                       
______________________________________                                    
dimethoxy      diacetoxy     silane                                       
methoxy        triacetoxy    silane                                       
______________________________________
Illustrative aminosilanes may include dimethyl diamino silane or dibutyl diaminosilane; illustrative hydroxy silanes may include diethyl dihydroxy silane or methyl trihydroxy silane.
Typical polyisocyanates may include, the first listed being preferred:
              TABLE                                                       
______________________________________                                    
toluene              diisocyanate                                         
phenylene            diisocyanate                                         
hexamethylene        diisocyanate                                         
toluene              tri-isocyanate                                       
______________________________________
Typical poly(carbonyl chlorides) may include, the first listed being preferred:
              TABLE                                                       
______________________________________                                    
adipoyl dichloride                                                        
isophthaloyl dichloride                                                   
suberoyl dichloride                                                       
______________________________________
Formation of the cross-linked elastomer silicone membrane may be carried out in a solution, in inert diluent-solvent (typified by a hydrocarbon such as commercial hexane) of 5-15, say 10 w % of the non-halogenated polysiloxane plus 1-10 w %, say 4 w % of cross-linking agent.
This solution may be solvent cast as a 0.5-4 mil, say 2 mil film onto a support layer (on a carrier layer) typically at say 25° C. Thereafter it is cured at 110° C.-140° C., say 125° C. for 10-20 minutes, say 15 minutes to form a film 1-5, say 1.5 thick.
The Composite Membrane
It is a feature of this invention that it may utilize a composite membrane which comprises (i) a carrier layer characterized by mechanical strength, for supporting a porous support layer and a separating layer (ii) a porous support layer such as a polyacrylonitrile membrane of 10-80 microns, and of molecular weight cut-off of 25,000-100,000, and (iii) as a non-porous separating layer a polysiloxane elastomer membrane which has been cross-linked with, as cross-linking agent, a polyisocyanate, or a poly(carbonyl chloride) or R4-a Si (A)a wherein A is --OH, --NH2 --OR, or --OOCR, a is 2, 3, or 4, and R is alkyl, aryl, cycloalkyl, alkaryl, or aralkyl.
It is possible to utilize a spiral wound module which includes a non-porous separating layer membrane mounted on a porous support layer and a carrier layer, the assembly being typically folded and bonded or sealed along all the edges but an open edge--to form a bag-like unit which preferably has the separating layer on the outside. A cloth spacer, serving as the permeate or discharge channel is placed within the bag-like unit. The discharge channel projects from the open end of the unit.
There then placed on one face of the bag-like unit, adjacent to the separating layer, and coterminous therewith, a feed channel sheet--typically formed of a plastic net.
The so-formed assembly is wrapped around a preferably cylindrical conduit which bears a plurality of perforations in the wall--preferably in a linear array which is as long as the width of the bag-like unit. The projecting portion of the discharge channel of the bag-like unit is placed over the perforations of the conduit; and the bag-like unit is wrapped around the conduit to form a spiral wound configuration. It will be apparent that, although only one feed channel is present, the single feed channel in the wound assembly will be adjacent to two faces of the membrane layer. The spiral wound configuration may be formed by wrapping the assembly around the conduit a plurality of times to form a readily handleable unit. The unit is fitted within a shell (in manner comparable to a shell-and-tube heat exchanger) provided with an inlet at one end and an outlet at the other. A baffle-like seal between the inner surface of the shell and the outer surface of the spiral-wound unit prevents fluid from bypassing the operative membrane system and insures that fluid enters the system principally at one end. The permeate passes from the feed channel, into contact with the separating layer and thence therethrough, into the permeate channel and thence therethrough to and through the perforations in the conduit through which it is withdrawn as net permeate.
In use of the spiral wound membrane, charge liquid is permitted to pass through the plastic net which serves as a feed channel and thence into contact with the non-porous separating membranes. The liquid which does not pass through the membranes is withdrawn as retentate. The liquid which permeates the membrane passes into the volume occupied by the permeate spacer and through this permeate channel to the perforations in the cylindrical conduit through which it is withdrawn from the system.
In another embodiment, it is possible to utilize the system of this invention as a tubular or hollow fibre. In this embodiment, the polyacrylonitrile porous support layer may be extruded as a fine tube with a wall thickness of typically 0.001-0.1 mm. The extruded tubes are passed through a bath of silicone which is cross-linked and cured in situ. A bundle or these tubes is secured (with an epoxy adhesive) at each end in a header; and the fibres are cut so that they are flush with the ends of the header. This tube bundle is mounted within a shell in a typical shell-and-tube assembly.
In operation, the charge liquid is admitted to the tube side and passes through the inside of the tubes and exits as retentate. During passage through the tubes, permeate passes through the non-porous separating layer and permeate is collected in the shell side.
Pressure Driven Process
It is a feature of the non-porous cross-linked elastomer separating layer that it is found to be particularly effective when used in a pressure driven process. In a pressure driven process, a charge liquid containing a more permeable and a less permeable component is maintained in contact with a non-porous separating layer; and a pressure drop is maintained across that layer. A portion of the charge liquid dissolves into the membrane and diffuses therethrough. The permeate passes through the membrane and exits as a liquid.
In practice of the process of this invention, the charge containing dewaxing solvent and dewaxed oil in liquid phase typically at 20° C.-40° C., say 25° C. may be passed into contact with the non-porous elastomer separating layer of the membrane of this invention. A pressure drop of about 500-1,000 psi, say 800 psi is commonly maintained across the membrane. The feed or charge side of the membrane is at pressure sufficient ot drive permeate across the membrane and commonly about 800 psig; and the permeate or discharge side of the membrane is at about atmospheric pressure. The feed is passed over the surface (ca three inches in diameter in one embodiment) of the membrane at a rate (e.g. of about 1,200 ml/min) which minimizes the possibility of concentration polarization.
The permeate which passes through the membrane includes increased content of dewaxing solvent and decreased content of dewaxed oil; and the retentate includes increased content of dewaxed oil and decreased content of dewaxing solvent.
Typically when the charge to the membrane contains (per 100 parts of oil) 100-1,100, preferably 200-600 parts, say 200 parts of dewaxing solvent, the permeate may be found to typically contain about 96 w % of dewaxing solvent.
Permeate is recovered in liquid phase.
Separation may typically be carried out at a flux of 20-40, say 37.1 kilograms per square meter per hour (kmh). Typically the membranes may have a rejection of more than 80% and commonly 70%-90%, say 89.7%. ##EQU1##
Practice of the process of this invention will be apparent to those skilled in the art from the following examples wherein, as elsewhere in this specification, all percentages are percentages by weight unless otherwise stated.
DESCRIPTION OF SPECIFIC EMBODIMENTS Example I
In this Example, which represents the best mode of carrying out the process of this invention, the elastomer separating membrane is formed on the DUY-L brand (of Daicel Corp.) composite which includes as carrier layer the woven polyester backing described supra. The porous support layer is the commercially available polyacrylonitrile (PAN) having a 40,000 molecular weight cut off.
The solution of elastomer in commercial hexane containing (i) 9 w % disilanol-terminated poly dimethyl siloxane (m.w. 1,750) and (ii) 4 w % 2,4-toluene diisocyanate is poured onto the porous support layer at 25° C. to coat a film of about 2 mil thickness, followed by heat curing at 125° C. for 15 minutes.
This membrane (three inch diameter circle) is mounted in a standard cell. There is admitted to the cell and to the non-porous elastomer separating layer a charge containing one part by weight of dewaxed SNO-100 oil and 1 part by weight of methyl ethyl ketone and 1 part by weight of toluene
Separation is carried out at room temperature of 25° C. and a charge (and retentate) pressure of about 800 psig. Feed is at 25° C./800 psig at flow rate of 1,200 ml/min. Permeate pressure is atmospheric. Selectivity is measured and reported as % Rejection which is calculated at 100×(the quantity of dewaxed oil in the feed minus the quantity of dewaxed oil in the permeate) divided by the quantity of dewaxed oil in the feed. Clearly a higher Selectivity is desired, as this means that the retentate desirably contains less dewaxing solvent and the permeate desirably contains more solvent. Flux is measured as kilograms per square meter per hour (kmh).
In this Example, the Selectivity is 89.7% rejection and the Flux is 37.1.
Examples II-V
In this series of Examples, the procedure of Example I is followed except that in Example II, the toluene diisocyanate is present in amount of 2%, in Examples III-IV the cross-linking agent is adipoyl dichloride (2 w % and 4 w % respectively) and in Example V, no cross-linking agent is employed.
              TABLE                                                       
______________________________________                                    
              Selectivity                                                 
                         Flux                                             
Example       % Rejection                                                 
                         (kmh)                                            
______________________________________                                    
I             89.7       37.1                                             
II            87.4       36.8                                             
III           84.2       39.1                                             
IV            83.5       37.2                                             
V*            68.2       29.6                                             
______________________________________                                    
 *Control Example
Examples VI-IX
In this series of Examples, the procedure of Example I is followed except that the polysiloxane is decamethyl cyclopentasiloxane ##STR4## present as 5 w % solution in commercial hexane which also contains 5 w % of a multifunctional cross-linking agent as noted in the Table which follows:
              TABLE                                                       
______________________________________                                    
       Cross-Linking    Selectivity Flux                                  
Example                                                                   
       Agent            (% Rejection)                                     
                                    (kmh)                                 
______________________________________                                    
VI     dimethyl diethoxy silane                                           
                        77.4        29.7                                  
VII    methyl triethoxy silane                                            
                        77.4        33.4                                  
VIII   dimethyl diacetoxy silane                                          
                        82.5        34.0                                  
IX*    no cross-linking agent                                             
                        77.4        30.6                                  
______________________________________
From inspection of Examples I-IX*, it will be apparent that the technique of this invention permits attainment of results (in terms of Selectivity and Flux) which are consistently higher than those attained when no cross-linking agent is employed. Best results appear to be attained in Examples I using a linear disilanol terminated poly dimethyl siloxane which has been cross-linked with toluene diisocyanate.
Examples X*-XV*
In this series of Examples, a series of silanol-terminated polydimethyl siloxanes of different molecular weight (in 10 w % hexane solution) were formed into similar elastomer membranes which were not chemically cross-linked.
              TABLE                                                       
______________________________________                                    
         Molecular    Selectivity Flux                                    
Example  Weight       (% Rejection)                                       
                                  (kmh)                                   
______________________________________                                    
X*       150,000      47.7        23.3                                    
XI*      110,000      48.5        26.3                                    
XII*      58,000      53.8        24.1                                    
XIII*     4,200       65.1        28.4                                    
XIV*      1,750       68.2        29.6                                    
XV*         550       70.6        31.4                                    
______________________________________
From inspection of Example X*-XV*, it is clear that uncross-linked silicone polymers yield results which are generally much less satisfactory.
Although this invention has been illustrated by reference to specific embodiments, it will be apparent to those skilled in the art that various charges and modifications may be made which clearly fall within the scope of the invention.

Claims (11)

What is claimed:
1. An elastomer membrane, which comprises a non-porous elastomer membrane layer of a polysiloxane which has been cross-linked with, as cross-linking agent, a polyisocyanate, (ii) a poly(carbonyl chloride), or (iii) a silane R4-a Si(A)a wherein A is --OH, --NH2, --OR, or --OOCR, a is 2, 3, or 4, and R is hydrogen or an alkyl, aralkyl, cycloalkyl, aryl, or alkaryl group, in proportions sufficient for providing properties enabling effective separation of dewaxing solvent and dewaxed oil.
2. A membrane as claimed in claim 1 wherein said polysiloxane is a cyclic polysiloxane.
3. A membrane as claimed in claim 1 wherein said polysiloxane is a linear polysiloxane.
4. A membrane as claimed in claim 1 wherein said polysiloxane is a silanol-terminated linear polysiloxane.
5. A membrane as claimed in claim 1 wherein said polysiloxane is a silanol-terminated linear dimethyl siloxane of molecular weight Mn of 550-4,200.
6. A membrane as claimed in claim 1 wherein said polysiloxane said cross-linking agent is a polyisocyanate.
7. A membrane as claimed in claim 1 wherein said cross-linking agent is a toluene diisocyanate.
8. A membrane as claimed in claim 1 wherein said cross-linking agent is a poly(carbonyl chloride).
9. A membrane as claimed in claim 1 wherein said cross-linking agent is adipoyl dichloride.
10. A membrane as claimed in claim 1 wherein said cross-linking agent is R4-a Si(A) wherein A is --OR or --OOCR, a is 2, 3, or 4, and R is hydrogen or an alkyl, aralkyl, cycloalkyl, aryl, or alkaryl group.
11. A membrane as claimed in claim 1 wherein said cross-linking agent is dimethyl diacetoxy silane.
US07/726,435 1991-04-29 1991-07-05 Membrane process for treating a mixture containing dewaxed oil and dewaxing solvent Expired - Fee Related US5093002A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US07/726,435 US5093002A (en) 1991-04-29 1991-07-05 Membrane process for treating a mixture containing dewaxed oil and dewaxing solvent

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US07/692,890 US5102551A (en) 1991-04-29 1991-04-29 Membrane process for treating a mixture containing dewaxed oil and dewaxing solvent
US07/726,435 US5093002A (en) 1991-04-29 1991-07-05 Membrane process for treating a mixture containing dewaxed oil and dewaxing solvent

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
US07/692,890 Division US5102551A (en) 1991-04-29 1991-04-29 Membrane process for treating a mixture containing dewaxed oil and dewaxing solvent

Publications (1)

Publication Number Publication Date
US5093002A true US5093002A (en) 1992-03-03

Family

ID=27105074

Family Applications (1)

Application Number Title Priority Date Filing Date
US07/726,435 Expired - Fee Related US5093002A (en) 1991-04-29 1991-07-05 Membrane process for treating a mixture containing dewaxed oil and dewaxing solvent

Country Status (1)

Country Link
US (1) US5093002A (en)

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5264166A (en) * 1993-04-23 1993-11-23 W. R. Grace & Co.-Conn. Polyimide membrane for separation of solvents from lube oil
FR2796862A1 (en) * 1999-07-26 2001-02-02 Centre Nat Rech Scient COMPOSITION OF POLYMER AND ITS USE FOR THE PREPARATION OF A PERMSELECTIVE MEMBRANE
WO2004055037A2 (en) 2002-12-18 2004-07-01 Avecia Limited Process for purifying oligonucleotide synthons
WO2007050450A2 (en) 2005-10-24 2007-05-03 Shell Internationale Research Maatschappij B.V. Methods of cracking a crude product to produce additional crude products
WO2008002154A2 (en) 2006-06-28 2008-01-03 Due Miljø As Deacidification method
US20080217016A1 (en) * 2006-10-20 2008-09-11 George Leo Stegemeier Creating fluid injectivity in tar sands formations
US20090012342A1 (en) * 2004-10-11 2009-01-08 Johannes Leendert Den Boestert Process to prepare a haze free base oil
US7533719B2 (en) 2006-04-21 2009-05-19 Shell Oil Company Wellhead with non-ferromagnetic materials
US20100105959A1 (en) * 2006-12-20 2010-04-29 Johannes Gerhardus Joseph Beckers Process for the removing poly(propylene oxide) from propylene oxide by membrane separation
US7735935B2 (en) 2001-04-24 2010-06-15 Shell Oil Company In situ thermal processing of an oil shale formation containing carbonate minerals
US20100147745A1 (en) * 2007-03-27 2010-06-17 Johannes Leendert Willem Cornelis Den Boestert Method for reducing the mercury content of natural gas condensate and natural gas processing plant
US7798220B2 (en) 2007-04-20 2010-09-21 Shell Oil Company In situ heat treatment of a tar sands formation after drive process treatment
US7866388B2 (en) 2007-10-19 2011-01-11 Shell Oil Company High temperature methods for forming oxidizer fuel
WO2012076532A1 (en) 2010-12-08 2012-06-14 Shell Internationale Research Maatschappij B.V. Process for purifying aryl group containing carbonates
WO2012076519A1 (en) 2010-12-08 2012-06-14 Shell Internationale Research Maatschappij B.V. Process for purifying dialkyl carbonate
US8627887B2 (en) 2001-10-24 2014-01-14 Shell Oil Company In situ recovery from a hydrocarbon containing formation
WO2021099255A1 (en) 2019-11-20 2021-05-27 Shell Internationale Research Maatschappij B.V. Process for removing poly(propylene oxide) from propylene oxide by membrane separation
US20220401895A1 (en) * 2019-09-25 2022-12-22 Shell Oil Company Process for reducing injector deposits

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4605526A (en) * 1984-10-15 1986-08-12 Shell Oil Company Process for producing dense membranes

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4605526A (en) * 1984-10-15 1986-08-12 Shell Oil Company Process for producing dense membranes

Cited By (93)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5264166A (en) * 1993-04-23 1993-11-23 W. R. Grace & Co.-Conn. Polyimide membrane for separation of solvents from lube oil
FR2796862A1 (en) * 1999-07-26 2001-02-02 Centre Nat Rech Scient COMPOSITION OF POLYMER AND ITS USE FOR THE PREPARATION OF A PERMSELECTIVE MEMBRANE
US7735935B2 (en) 2001-04-24 2010-06-15 Shell Oil Company In situ thermal processing of an oil shale formation containing carbonate minerals
US8608249B2 (en) 2001-04-24 2013-12-17 Shell Oil Company In situ thermal processing of an oil shale formation
US8627887B2 (en) 2001-10-24 2014-01-14 Shell Oil Company In situ recovery from a hydrocarbon containing formation
WO2004055037A2 (en) 2002-12-18 2004-07-01 Avecia Limited Process for purifying oligonucleotide synthons
US20090012342A1 (en) * 2004-10-11 2009-01-08 Johannes Leendert Den Boestert Process to prepare a haze free base oil
US7635025B2 (en) 2005-10-24 2009-12-22 Shell Oil Company Cogeneration systems and processes for treating hydrocarbon containing formations
US7549470B2 (en) 2005-10-24 2009-06-23 Shell Oil Company Solution mining and heating by oxidation for treating hydrocarbon containing formations
WO2007050450A2 (en) 2005-10-24 2007-05-03 Shell Internationale Research Maatschappij B.V. Methods of cracking a crude product to produce additional crude products
WO2007050449A2 (en) 2005-10-24 2007-05-03 Shell Internationale Research Maatschappij B.V. Methods of producing alkylated hydrocarbons from a liquid produced from an in situ heat treatment
US7556096B2 (en) 2005-10-24 2009-07-07 Shell Oil Company Varying heating in dawsonite zones in hydrocarbon containing formations
US7559368B2 (en) 2005-10-24 2009-07-14 Shell Oil Company Solution mining systems and methods for treating hydrocarbon containing formations
US7559367B2 (en) 2005-10-24 2009-07-14 Shell Oil Company Temperature limited heater with a conduit substantially electrically isolated from the formation
US8151880B2 (en) 2005-10-24 2012-04-10 Shell Oil Company Methods of making transportation fuel
US7556095B2 (en) 2005-10-24 2009-07-07 Shell Oil Company Solution mining dawsonite from hydrocarbon containing formations with a chelating agent
US20080017370A1 (en) * 2005-10-24 2008-01-24 Vinegar Harold J Temperature limited heater with a conduit substantially electrically isolated from the formation
US7562706B2 (en) 2005-10-24 2009-07-21 Shell Oil Company Systems and methods for producing hydrocarbons from tar sands formations
US7581589B2 (en) 2005-10-24 2009-09-01 Shell Oil Company Methods of producing alkylated hydrocarbons from an in situ heat treatment process liquid
US7584789B2 (en) 2005-10-24 2009-09-08 Shell Oil Company Methods of cracking a crude product to produce additional crude products
US7591310B2 (en) 2005-10-24 2009-09-22 Shell Oil Company Methods of hydrotreating a liquid stream to remove clogging compounds
US8606091B2 (en) 2005-10-24 2013-12-10 Shell Oil Company Subsurface heaters with low sulfidation rates
US8083813B2 (en) 2006-04-21 2011-12-27 Shell Oil Company Methods of producing transportation fuel
US7597147B2 (en) 2006-04-21 2009-10-06 Shell Oil Company Temperature limited heaters using phase transformation of ferromagnetic material
US7631689B2 (en) 2006-04-21 2009-12-15 Shell Oil Company Sulfur barrier for use with in situ processes for treating formations
US7912358B2 (en) 2006-04-21 2011-03-22 Shell Oil Company Alternate energy source usage for in situ heat treatment processes
US7635023B2 (en) 2006-04-21 2009-12-22 Shell Oil Company Time sequenced heating of multiple layers in a hydrocarbon containing formation
US7604052B2 (en) 2006-04-21 2009-10-20 Shell Oil Company Compositions produced using an in situ heat treatment process
US7866385B2 (en) 2006-04-21 2011-01-11 Shell Oil Company Power systems utilizing the heat of produced formation fluid
US7610962B2 (en) 2006-04-21 2009-11-03 Shell Oil Company Sour gas injection for use with in situ heat treatment
US8192682B2 (en) 2006-04-21 2012-06-05 Shell Oil Company High strength alloys
US7673786B2 (en) 2006-04-21 2010-03-09 Shell Oil Company Welding shield for coupling heaters
US7785427B2 (en) 2006-04-21 2010-08-31 Shell Oil Company High strength alloys
US8857506B2 (en) 2006-04-21 2014-10-14 Shell Oil Company Alternate energy source usage methods for in situ heat treatment processes
US7533719B2 (en) 2006-04-21 2009-05-19 Shell Oil Company Wellhead with non-ferromagnetic materials
US7683296B2 (en) 2006-04-21 2010-03-23 Shell Oil Company Adjusting alloy compositions for selected properties in temperature limited heaters
US7793722B2 (en) 2006-04-21 2010-09-14 Shell Oil Company Non-ferromagnetic overburden casing
WO2008002154A2 (en) 2006-06-28 2008-01-03 Due Miljø As Deacidification method
US7540324B2 (en) 2006-10-20 2009-06-02 Shell Oil Company Heating hydrocarbon containing formations in a checkerboard pattern staged process
US7635024B2 (en) 2006-10-20 2009-12-22 Shell Oil Company Heating tar sands formations to visbreaking temperatures
US7730946B2 (en) 2006-10-20 2010-06-08 Shell Oil Company Treating tar sands formations with dolomite
US7730947B2 (en) 2006-10-20 2010-06-08 Shell Oil Company Creating fluid injectivity in tar sands formations
US7717171B2 (en) 2006-10-20 2010-05-18 Shell Oil Company Moving hydrocarbons through portions of tar sands formations with a fluid
US20080217016A1 (en) * 2006-10-20 2008-09-11 George Leo Stegemeier Creating fluid injectivity in tar sands formations
US8191630B2 (en) 2006-10-20 2012-06-05 Shell Oil Company Creating fluid injectivity in tar sands formations
US7703513B2 (en) 2006-10-20 2010-04-27 Shell Oil Company Wax barrier for use with in situ processes for treating formations
US7681647B2 (en) 2006-10-20 2010-03-23 Shell Oil Company Method of producing drive fluid in situ in tar sands formations
US7562707B2 (en) 2006-10-20 2009-07-21 Shell Oil Company Heating hydrocarbon containing formations in a line drive staged process
US7677310B2 (en) 2006-10-20 2010-03-16 Shell Oil Company Creating and maintaining a gas cap in tar sands formations
US7677314B2 (en) 2006-10-20 2010-03-16 Shell Oil Company Method of condensing vaporized water in situ to treat tar sands formations
US7841401B2 (en) 2006-10-20 2010-11-30 Shell Oil Company Gas injection to inhibit migration during an in situ heat treatment process
US7845411B2 (en) 2006-10-20 2010-12-07 Shell Oil Company In situ heat treatment process utilizing a closed loop heating system
US7673681B2 (en) 2006-10-20 2010-03-09 Shell Oil Company Treating tar sands formations with karsted zones
US7644765B2 (en) 2006-10-20 2010-01-12 Shell Oil Company Heating tar sands formations while controlling pressure
US7730945B2 (en) 2006-10-20 2010-06-08 Shell Oil Company Using geothermal energy to heat a portion of a formation for an in situ heat treatment process
US8555971B2 (en) 2006-10-20 2013-10-15 Shell Oil Company Treating tar sands formations with dolomite
US7631690B2 (en) 2006-10-20 2009-12-15 Shell Oil Company Heating hydrocarbon containing formations in a spiral startup staged sequence
US8304564B2 (en) 2006-12-20 2012-11-06 Shell Oil Company Process for the removing poly(propylene oxide) from propylene oxide by membrane separation
US20100105959A1 (en) * 2006-12-20 2010-04-29 Johannes Gerhardus Joseph Beckers Process for the removing poly(propylene oxide) from propylene oxide by membrane separation
US9034175B2 (en) 2007-03-27 2015-05-19 Shell Oil Company Method for reducing the mercury content of natural gas condensate and natural gas processing plant
US20100147745A1 (en) * 2007-03-27 2010-06-17 Johannes Leendert Willem Cornelis Den Boestert Method for reducing the mercury content of natural gas condensate and natural gas processing plant
US7798220B2 (en) 2007-04-20 2010-09-21 Shell Oil Company In situ heat treatment of a tar sands formation after drive process treatment
US7841425B2 (en) 2007-04-20 2010-11-30 Shell Oil Company Drilling subsurface wellbores with cutting structures
US9181780B2 (en) 2007-04-20 2015-11-10 Shell Oil Company Controlling and assessing pressure conditions during treatment of tar sands formations
US7832484B2 (en) 2007-04-20 2010-11-16 Shell Oil Company Molten salt as a heat transfer fluid for heating a subsurface formation
US8042610B2 (en) 2007-04-20 2011-10-25 Shell Oil Company Parallel heater system for subsurface formations
US7841408B2 (en) 2007-04-20 2010-11-30 Shell Oil Company In situ heat treatment from multiple layers of a tar sands formation
US8791396B2 (en) 2007-04-20 2014-07-29 Shell Oil Company Floating insulated conductors for heating subsurface formations
US7950453B2 (en) 2007-04-20 2011-05-31 Shell Oil Company Downhole burner systems and methods for heating subsurface formations
US8662175B2 (en) 2007-04-20 2014-03-04 Shell Oil Company Varying properties of in situ heat treatment of a tar sands formation based on assessed viscosities
US7849922B2 (en) 2007-04-20 2010-12-14 Shell Oil Company In situ recovery from residually heated sections in a hydrocarbon containing formation
US8459359B2 (en) 2007-04-20 2013-06-11 Shell Oil Company Treating nahcolite containing formations and saline zones
US8381815B2 (en) 2007-04-20 2013-02-26 Shell Oil Company Production from multiple zones of a tar sands formation
US8327681B2 (en) 2007-04-20 2012-12-11 Shell Oil Company Wellbore manufacturing processes for in situ heat treatment processes
US7931086B2 (en) 2007-04-20 2011-04-26 Shell Oil Company Heating systems for heating subsurface formations
US8113272B2 (en) 2007-10-19 2012-02-14 Shell Oil Company Three-phase heaters with common overburden sections for heating subsurface formations
US8011451B2 (en) 2007-10-19 2011-09-06 Shell Oil Company Ranging methods for developing wellbores in subsurface formations
US8240774B2 (en) 2007-10-19 2012-08-14 Shell Oil Company Solution mining and in situ treatment of nahcolite beds
US8146661B2 (en) 2007-10-19 2012-04-03 Shell Oil Company Cryogenic treatment of gas
US8536497B2 (en) 2007-10-19 2013-09-17 Shell Oil Company Methods for forming long subsurface heaters
US7866386B2 (en) 2007-10-19 2011-01-11 Shell Oil Company In situ oxidation of subsurface formations
US7866388B2 (en) 2007-10-19 2011-01-11 Shell Oil Company High temperature methods for forming oxidizer fuel
US8146669B2 (en) 2007-10-19 2012-04-03 Shell Oil Company Multi-step heater deployment in a subsurface formation
US8272455B2 (en) 2007-10-19 2012-09-25 Shell Oil Company Methods for forming wellbores in heated formations
US8276661B2 (en) 2007-10-19 2012-10-02 Shell Oil Company Heating subsurface formations by oxidizing fuel on a fuel carrier
US8196658B2 (en) 2007-10-19 2012-06-12 Shell Oil Company Irregular spacing of heat sources for treating hydrocarbon containing formations
US8162059B2 (en) 2007-10-19 2012-04-24 Shell Oil Company Induction heaters used to heat subsurface formations
WO2012076532A1 (en) 2010-12-08 2012-06-14 Shell Internationale Research Maatschappij B.V. Process for purifying aryl group containing carbonates
WO2012076519A1 (en) 2010-12-08 2012-06-14 Shell Internationale Research Maatschappij B.V. Process for purifying dialkyl carbonate
US20220401895A1 (en) * 2019-09-25 2022-12-22 Shell Oil Company Process for reducing injector deposits
US12023632B2 (en) * 2019-09-25 2024-07-02 Shell Usa, Inc. Process for reducing injector deposits
WO2021099255A1 (en) 2019-11-20 2021-05-27 Shell Internationale Research Maatschappij B.V. Process for removing poly(propylene oxide) from propylene oxide by membrane separation
US12378212B2 (en) 2019-11-20 2025-08-05 Shell Usa, Inc. Process for removing poly(propylene oxide) from propylene oxide by membrane separation

Similar Documents

Publication Publication Date Title
US5102551A (en) Membrane process for treating a mixture containing dewaxed oil and dewaxing solvent
US5093002A (en) Membrane process for treating a mixture containing dewaxed oil and dewaxing solvent
US4644046A (en) Ultrathin film, process for production thereof, and use thereof for concentrating a specific gas from a gas mixture
JP2718681B2 (en) Thin film composite separation membrane and separation method using the same
US4985138A (en) Process for treating a charge containing dewaxing solvent and dewaxed oil
US4929357A (en) Isocyanurate crosslinked polyurethane membranes and their use for the separation of aromatics from non-aromatics
EP0125908B1 (en) Asymmetric polyimide reverse osmosis membrane, method for preparation of same and use thereof for organic liquid separations
EP0631806B1 (en) The production and use of improved composite fluid separation membranes
US4510047A (en) Selective extraction solvent recovery using regenerated cellulose membrane under reverse osmosis conditions
US4897091A (en) Membrane process for separating gases from gas-liquid charge streams
EP0439905B1 (en) Separation of furfural/middle distillate streams
EP0220753B1 (en) Process for the separation of solvents from hydrocarbons dissolved in said solvents
FR2587232A1 (en) SEMI-PERMEABLE FILTRATION MEMBRANE, NOT SUBSTANTIALLY PROTECTING ADHESIVES, SEMI-PERMEABLE MEMBRANE, ULTRAFILTRATION HOLLOW FIBER ANISOTROPIDE NOT SUBSTANTIALLY PROTECTING PROTEINS AND PROCESS FOR PRODUCING SAME
AU617497B2 (en) Composite semipermeable membranes and method of making same
US5063186A (en) Highly aromatic polyurea/urethane membranes and their use of the separation of aromatics from non-aromatics
US5146038A (en) Process for treating a mixture containing dewaxed oil and dewaxing solvent
JPH07114937B2 (en) Separation membrane
EA005984B1 (en) Epoxysilicone coated membranes, method for preparing same and membrane separation process
EP0413858A1 (en) Method of treating dilute aqueous solution
US4606903A (en) Membrane separation of uncoverted carbon fiber precursors from flux solvent and/or anti-solvent
US4983338A (en) Isocyanurate crosslinked polyurethane membranes and their use for the separation of aromatics from non-aromatics
US5234579A (en) Membrane process for treating a charge containing dewaxing solvent and dewaxed oil
US5238567A (en) Membrane process for separating a mixture containing dewaxed oil and dewaxing solvent
US5240591A (en) Membrane process for separating a mixture containing dewaxed oil and dewaxing solvent
US4810366A (en) Process for separating a fluid feed mixture containing hydrocarbon oil and an organic solvent

Legal Events

Date Code Title Description
CC Certificate of correction
REMI Maintenance fee reminder mailed
LAPS Lapse for failure to pay maintenance fees
FP Lapsed due to failure to pay maintenance fee

Effective date: 19960306

STCH Information on status: patent discontinuation

Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362